1. Field of the Invention
The present invention relates generally to regeneration of adsorbents, and more particularly, to a method of removing organic materials by adsorbents and regenerating the adsorbents using advanced oxidation.
2. Description of the Related Art
In the past, it has been desired to remove organic materials such as toxic organic contaminants from fluids such as water or air. One method which has been used for removing organic material from water or air is adsorption using adsorbents such as granular activated carbon (GAC). An example of such a method is disclosed in U.S. Pat. No. 4,861,484 to Lichten et al., the disclosure of which is hereby incorporated by reference. The Lichten et al. patented method includes treating water polluted with organic material by passing the polluted water through GAC such that the organic material is removed and adsorbed onto the GAC.
One problem with using GAC to remove organic material from water or air is that the spent GAC is, in some cases, considered as hazardous waste and requires proper disposal and/or treatment. For example, the spent GAC may be disposed in a hazardous waste landfill or incinerated. For large water treatment facilities, on-site thermal reactivation of the adsorbed GAC may be used.
However, for small water treatment utilities, GAC usage rates may not be large enough to justify on-site thermal reactivation. Also, hazardous waste landfills or incinerators may not be available. Therefore, a need exists for on-site regeneration of spent adsorbents such as GAC and the destruction of the adsorbed organic material.
One attempt to regenerate spent adsorbents is disclosed in the above-identified Lichten et al. '484 patent. The Lichten et al. patented method includes mixing the adsorbed GAC with an organic solvent such that the organic material becomes dissolved in the organic solvent and the GAC is regenerated in a form substantially free of adsorbed organic material.
One problem with the above patented method is that the organic solvent has to be treated or disposed to destroy the organic material. This is undesirable and costly since extra handling and process steps are used. Another problem is that an organic solvent has to be used to regenerate the GAC. This is also undesirable, costly, and requires additional handling.